The present invention relates to an articulator making it possible to parametrize the prosthetic or occlusal orientation plane and the dentoalveolar stages for the purpose of producing dental prostheses.
For the production of dental prostheses, use is made at the present time of articulators of the xe2x80x9cARCONxe2x80x9d type, employed most often, or else xe2x80x9cNONARCONxe2x80x9d type. These appliances, used in dental prosthesis laboratories and in dental surgeries, serve for reproducing the envelope of natural physiological movements between the dental arches of a patient in relation to his skull, for the purpose of manufacturing bridges, prostheses, etc. in a laboratory.
These appliances generally comprise two planar elements or members, respectively lower and upper, which are articulated relative to one another about a horizontal axis parallel to the plane of the two elements and located at a level higher than that of the lower planar element. Plaster models of a patient""s dental arches are fastened to these upper and lower planar elements which reproduce as it were the patient""s jaws. These models comprise an upper model, reproducing the upper dental arch and fastened under the lower face of the upper element, and a lower model, reproducing the lower dental arch and fastened to the upper face of the lower element. When the number of antagonistic teeth allows it, there is natural wedging between the middle stage of the face and the lower stage of the face. This preserves the vertical occlusal dimension which is conducive to the esthetic appearance of the face. This vertical dimension is therefore transferred to the articulator, when the plaster models of the patient""s dental arches are mounted, by means of the facial arch and in occlusion. On the articulator, the two models of the patient are fastened opposite one another, so as to come into contact with one another along an occlusal plane which corresponds to the occlusal plane of the patient""s dental arches. Cephalometry is the study of the craniofacial structures on X-ray photographs of the head, profile or face. It is possible, on a profile teleradiogram, to trace the horizontal Frankfurt plane, which passes through the top of the image of the right and left external auditory meatuses and the images of the infraorbital foramens, and also the patient""s occlusal plane defined as the occlusal plane traced by recording the intermeshing zone of the first molars and central incisors. In a patient with normodivergent teeth, the occlusal plane is the plane of contact between the top teeth and the bottom teeth, and it is generally inclined from the top downward and from the rear forward at an angle of 10xc2x0 in relation to the horizontal Frankfurt plane.
There are on the market accessories which make it possible to parametrize the occlusal plane, but these accessories do not make it possible to parametrize as easily between the two mounted dental arch models; nor do they make it possible to manufacture in a laboratory occlusal mock-ups or temporary bridges which conform to the parametrization defined by the practitioner""s study. Nor is it possible for these accessories to make it possible to trace the prosthetic orientation plane on the plaster models of the patient""s dental arches.
In the articulators known at the present time, the upper plaster model mounted on a plate fastened to the lower element of the articulator, at a predetermined height above this element and inclined at an angle of 10xc2x0 from the top downward and from the rear forward in relation to the upper element, is useful only for a normodivergent patient whose upper arch occupies spatially the position in relation to the skull which this standard plate imposes on it. In fact, such a fixed height and such a fixed inclination do not correspond to the generality of cases encountered in practice in the various patients treated, who have a craniofacial scheme which may range from hypodivergence to hyperdivergence. In such circumstances, mounting the maxillary model of the patient""s dental arch along this standard plane is tantamount to neglecting the spatial position of the maxillary arch in relation to the base of the skull. In other words, a standard plane of a typical normodivergent patient is used for everybody. Such a plate, fixed in terms of height and inclination, therefore leads to a correct mounting of dental prostheses being impossible.
The present invention aims to overcome these disadvantages by providing an articulator making it possible to define a prosthetic orientation plane parametrizable as desired, both in millimeters of height and in degrees of inclination, taking into account the patient""s morphology (hyperdivergent, hypodivergent or normodivergent).
To this effect, this articulator, making it possible to parametrize the prosthetic or occlusal orientation plane and the dentoalveolar stages for the purpose of producing dental prostheses, comprises:
two upper and lower planar elements articulated relative to one another about a horizontal axis parallel to the planes of the elements and located above the lower planar element, the two planar elements being intended for fastening two models of a patient""s dental arches opposite one another and in contact with one another, specifically an upper model fastened under the lower face of the upper element and a lower model fastened on the upper face of the lower element,
means for defining, between the two elements, a plane inclined relative to the upper element and corresponding to an occlusal plane between the two models, said means being carried by the upper element and comprising a plate embodying the occlusal orientation plane.
According to the invention, the means defining the inclined plane comprise means for adjusting the angle of inclination and the distance of the plate in relation to the upper element, and the adjustment of the distance of the plate in relation to the upper element is ensured by means of at least one assembly carried by the upper element and a graduated column carrying at its lower end the plate and sliding perpendicularly to the upper element in the assembly, thus ensuring the guidance of the column and the locking of the latter in a position adjustable relative to the upper element.
The articulator according to the invention makes it possible to manufacture occlusal mock-ups along a prosthetic orientation plane suitable for each patient, this being achieved by means of a double movement about an axis which does not disturb the angular programming selected for the prosthetic orientation plane. The articulator may additionally comprise a compass making it possible to trace the prosthetic orientation plane and the orientation of the line of the gingivodental collars. It also makes it possible to use an anteroposterior sagittal axis allowing the distortion of an occlusal plane, that is to say its asymmetry relative to the base of the skull, to be diagnosed.
The articulator according to the invention makes it possible to obtain a time saving and constant reliability at all the stages of the prosthetic reconstruction work. In its use in orthodontics, by recording the occlusal plane before treatment (coordinates in millimeters of height and degrees of inclination), the orthodontist can, during treatment or after treatment, check the action of the orthodontic appliance in the mouth by once again transferring the spatial situation of the patient""s dental arches to the articulator and by carrying out a comparison with initial values (in particular, dentoalveolar compensations).
The articulator according to the invention also makes it possible to diagnose and quantify the asymmetries of the occlusal plane which are responsible inter alia for dental traumatisms having effects on the dental arches and the temporomandibular joints. It also makes it possible to establish a surgical and prosthetic treatment plane before treatment. Stringent parametrization makes it possible to systematize the surgical, orthodontic or prosthetic modifications which a treating doctor considers for his patient.
The appliance is simple and quick to use, which cannot fail to be noticed by practitioners, whatever their field (implant surgery or periodontal, prosthetic or orthodontic surgery), and by prosthesists. Communication regarding the transfer of the patient""s models between a dental surgery and a prosthesis laboratory is greatly improved thereby.